The invention relates to a fuel injection pump having a pump work chamber enclosed by a pump piston in a cylinder, having a fuel distributing arrangement for connecting the pump work chamber with one or more fuel injection locations, and having a fuel supply arrangement for connecting the pump work chamber with a fuel supply to establish the fuel injection quantity. The fuel supply arrangement includes a fuel supply line of the pump work chamber, a fuel supply pump for supplying fuel to the fuel supply line, a pressure control device for adjusting the supply pressure of the fuel supply pump, a valve disposed in the fuel supply line, and an electric control device for controlling the actuation of the valve.
In an injection pump of this kind, such as that known from German Offenlegungsschrift 19 17 927, the fuel quantity to be injected during the supply stroke of the pump piston of the injection pump is determined by a first magnetic valve, which controls the onset of injection, and by a second magnetic valve, controlling the end of injection. At the onset of injection, the first magnetic valve closes the connection between the pump work chamber and the suction chamber of the injection pump, while the second magnetic valve is closed during this time. At the end of injection, the second magnetic valve then opens and relieves the pump work chamber toward the pump suction chamber. For this kind of control of a fuel injection pump, very rapidly switching magnetic valves which are also very forceful are required; furthermore, in order to avoid having dead spaces, such valves must be disposed with the closing member in the immediate vicinity of the mouth of the fuel supply line in the pump work chamber. The magnetic valves used in the known fuel injection pump have closing members which are directly exposed in their direction of movement to the working pressure in the pump work chambers. In order to keep these closing members in the closing position, great magnetic forces, reinforced by spring forces, are required. Accordingly, the magnets are very large and are difficult to accommodate in the injection pump itself.